The goal of this training grant program is to prepare outstanding M.D, M.D-Ph.D. and Ph.D. trainees for careers as scientific leaders in HIV/AIDS research. Despite enormous progress over the last 3 decades towards reducing the morbidity and mortality from HIV/AIDS, substantial challenges remain. These include developing a safe and effective vaccine; development of a cure for HIV infection; improving the treatment and management of opportunistic infections such as tuberculosis that burden HIV-infected patients in resource- limited settings; managing the threat of antiretroviral drug resistance; and developing safe and effective interventions to reduce the inappropriate immune activation that accompanies HIV infection and leads to end- organ disease. Progress on these fronts requires basic and translational research to further our understanding of the molecular biology, pathogenesis, immunology, prevention and therapeutics of HIV/AIDS. Over the past 25 years this program has trained 84 post-doctoral fellows, the majority of whom have gone on to leadership positions in academia, industry and government. This program will provide in-depth laboratory experience in a specific research area of HIV-related virology, immunology, epidemiology, molecular genetics, molecular therapeutics, genomics and/or systems biology. Criteria for selecting trainees will include prior training record, aptitude for research and demonstrated commitment to a research career. All applicants will be selected by a Training Advisory Committee (TAC); 7 trainees will be selected annually. Particular emphasis will be given to the recruitment of minorities and others underrepresented in AIDS research, including women, individuals with disabilities and those from disadvantaged backgrounds. Basic elements of the program include: 1) in-depth research training through laboratory investigation of a specific scientific question in a particular area of AIDS research under mentorship of a senior investigator; 2) a didactic program consisting of appropriately chosen courses specific to the trainee's career goals; 3) frequent exposure to seminars, workshops and colloquia related to AIDS; regular review of progress by individual Research Advisory Committees and the TAC. The training facilities consist of state-of-the-art research laboratories at Harvard Medical School Harvard School of Public Health, Beth Israel-Deaconess Hospital, Brigham and Women's Hospital, Dana Farber Cancer Institute, Massachusetts General Hospital and the Ragon Institute of MGH, Harvard and MIT. Independently funded senior and junior faculty at each of these institutions constitute the faculty of this training program, and represent a variety of AIDS related disciplines. The faculty collaborate extensively with one another on AIDS research and will collaborate in directing this training program. The Harvard Center for AIDS Research and the Harvard Medical School Clinical and Translational Science Center (Harvard Catalyst) provide additional institutional resources that enrich the scientific experience and career development of our trainees.